Stemming

Overview

Time: min

Objectives

What is Stemming?

Stemming is the process of reducing tokens to root forms. For example - studying and studied are converted to study. There are two commonly used stemming techniques in python.

• Porter Stemming
• Lancaster Stemming

Among these, Lancaster stemming is more aggresive, with twice the rules as porter stemmer and tends to over stem words -

Porter Stemming

from nltk.stem import PorterStemmer
pst = PorterStemmer()
stm = ["giving", "given", "given", "gave"]
for word in stm :
   print(word+ ":" +pst.stem(word))

Lancaster Stemming

from nltk.stem import LancasterStemmer
lst = LancasterStemmer()
stm = ["giving", "given", "given", "gave"]
for word in stm :
 print(word+ ":" +lst.stem(word))

Key Points